Hours before the meeting, believers and non-believers alike streamed into the square before dawn for Francis' Mass, and they erupted in cheers when history's first Latin-American pope spun through the crowd in his open-sided popemobile.

Francis did not disappoint, winding his way slowly through the masses and stopping to kiss children held up to him.

While most Cubans are nominally Catholic, fewer than 10% practise their faith.

The crowd was not as big as when St John Paul II became the first pope to visit the island in 1998, but it drew people who seemed to genuinely want to be there and listen to Francis' message.

"This is very important for us," said Mauren Gomez (40) who travelled 155 miles from Villa Clara to Havana by bus.

In his homily delivered under the gaze of the plaza's metal portrait of Che Guevara, Francis urged Cubans to care for one another out of a sense of service, not ideology. He encouraged them to refrain from judging one another by "looking to one side or the other to see what our neighbour is doing or not doing".

"Whoever wishes to be great must serve others, not be served by others," he said, explaining that "service is never ideological, for we do not serve ideas, we serve people".